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Bureau of Mines Information Circular/1986 




Antimony Availability- 
Market Economy Countries 

A Minerals Availability Appraisal 

By CM. Palencia and C.P. Mishra 




UNITED STATES DEPARTMENT OF THE INTERIOR 



Information Circular 19098 



Antimony Availability- 
Market Economy Countries 

A Minerals Availability Appraisal 

By CM. Palencia and C.P. Mishra 




UNITED STATES DEPARTMENT OF THE INTERIOR 
Donald Paul Model, Secretary 

BUREAU OF MINES 
Robert C. Morton, Director 



As the Nation's principal conservation agency, the Department of the Interior has 
responsibility for most of ovir nationally owned public lands and natural resources. This 
includes fostering the wisest use of oxu- land and water resources, protecting our fish 
and wildlife, preserving the environment and cultural values of our national parks and 
historical places, and providing for the enjoyment of life through outdoor recreation 
The Department assesses our energy and mineral resovirces and works to assvu-e that 
their development is in the best interests of all our people. The Department also has 
a major responsibility for American Indian reservation communities and for people who 
live in island territories under U.S. administration. 




Library of Congress Cataloging in Publication Data 



Palencia, Cesar M. 

Antimony availability— market economy covmtries. 



(Information circular/Bureau of Mines ; 9098 ) 

Bibliography: p. 20 

Supt. of Docs, no.: 128.27:9098 

1. Antimony. I. Mishra, C.P. (Chamundeshwari P.) 11. Title, m. 
Series: Information circvilar (United States. Bureau of Mines) ;|9098. 

TN295.U4 [TN490.A6] 622 s [338.2747] 86-600191 



PREFACE 



The Biireau of Mines is assessing the worldwide availability of selected minerals 
of economic significance, most of which are also critical minerals. The Bureau iden- 
tifies, collects, compiles, and evaluates information on producing, developing, and ex- 
plored deposits, and on mineral processing plants worldwide. Objectives are to classify 
both domestic and foreign resovirces, to identify by cost evaluation those demonstrated 
resoiu*ces that are reserves, and to prepare analyses of mineral availability. 

This report is one of a continuing series of reports that analyze the availability of 
minerals from domestic and foreign sources. Questions about, or comments on, these 
reports should be addressed to Chief, Division of Minerals Availability, Bureau of Mines, 
2401 E St., NW., Washington, DC 20241. 



CONTENTS 



Page 

Preface iii i 

Abstract 1 

Introduction 2: 

Commodity overview 2 

Products and uses • 2 

Substitutes 3| 

U.S. production, consumption, and trade 3' 

Market structure 3' 

Price structure 4 

Geology 4 

Deposit geology 4 

Australia 4| 

Hillgrove Mine 4 

Wild Cattle Creek Mine . , 5| 

Bolivia 5| 

Candelaria Mine 5| 

Caracota Mine 51 

Chilcobija Mine 5| 

Churquini Mine 5( 

Espiritu Santo Mine 6 

La Salvadora Mine 61 

Rosa de Oro Mine 61 

Canada 6 

Lake George Mine 6| 

Italy 6| 

Manciano Mine 6| 

Mexico 71 

Wadley Mine 7i 

Morocco 7/ 

Timerhoudine Mine 7/ 



Page 

Tourtit Mine 7 

Republic of South Africa 7 

Consolidated Murchison Ltd. Mines 7 

Thailand 8 

Bo Thong Mine 9 

Doi Ngoem Mine 8 

Mae Ta Mine 8 

Turkey 8 

Turhal-Tokat Mines 8 

United States 8 

Stibnite Hill Mine 8 

Yellow Pine Mine 9 

Mineralogy 9 

Resources 9 

Primary antimony 9 

Byproduct antimony 12 

Secondary antimony 12 

Mining and processing technology 13 

Mining 13 

Ore processing 14 

Smelting 14 

Refining 14 

Deposit evaluation procedure 14 

Capital and operating costs 17 

Antimony availability 18 

Total availability 18 

Annual availability 18 

Conclusions 20 

References 20 



ILLUSTRATIONS 

Page 

1. Antimony mine and deposit locations 11 

2. Demonstrated antimony resources 11 

3. Inferred antimony resources 12 

4. Minerals availability program I deposit {evaluation) procedure 15 

5. Mineral resource classification categories 16 

6. Total recoverable demonstrated antimony resoiu-ces from producing and nonproducing properties 18 

7. Potential annual availability from producing properties at a 15-pct DCFROR 19 

8. Potential annual availability from nonproducing properties at a 15-pct DCFROR 19 



TABLES 

Page 

1. Reported industrial consumption of primary antimony in the United States by end use, 1974-84 '2 

2. Salient antimony statistics, 1975-84 3 

3. Estimated antimony annual production capacities 4 

4. U.S. antimony prices. 1975-84 4 

5. Antimony minerals 9 

6. Deposits selected for evaluation 10 

7. Antimony resources 10 

8. Antimony produced as b5rproduct at primary lead refineries in the United States, 1975-81 ,13 

9. Secondary antimony produced in the United States by kind of scrap and form of recovery, 1975-83 113 

10. Estimated weighted-average operating and total production costs 117 

11. Primary antimony potentially available from mines and deposits at selected cost ranges, including a 15-pct 

DCFROR 118 

12. Potential annual production capacity for primary antimony at a 15-pct DCFROR 1 18/ 

13. Distribution of potential annucd capacity from producers and nonproducers at a 15-pct DCFROR J19 



VI 



UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 


op 


degree Fahrenheit 


min 


minute 


ft 


foot 


mt 


metric ton 


g/mt 


gram per metric ton 


mt/d 


metric ton per day 


h 


hour 


mt/5T 


metric ton per year 


kg 


kilogram 


mtu 


metric ton unit 


kg/mt 


kilogram per metric ton 


ppm 


part per million 


km 


kilometer 


tr oz 


troy ounce 


lb 


pound 


yr 


year 


m 


meter 







ANTIMONY AVAILABILITY— MARKET ECONOMY COUNTRIES 
A Minerals Availability Appraisal 

By C. M. Palencia^ and C. P. Mishra^ 



ABSTRACT 



The Bureau of Mines studied the potential availability of primary antimony (Sb) 
from demonstrated resources in 21 mines and deposits in market economy countries 
(MEC's). Twelve of these properties were evaluated as producers and nine as non- 
producers. The 21 studied properties contain 499,600 mt Sb as demonstrated resources, 
of which 304,000 mt is recoverable as antimony metal; another 973,500 mt Sb is con- 
tained in inferred resources. 

Recoverable antimony from demonstrated U.S. deposits is only 10,700 mt, just 3.5 
pet of the MEC total. Domestic production of primary antimony from operating mines 
has averaged only 561 mt/5T over the 10-yr period 1975-84. This represents just over 
5 pet of total U.S. consumption of primary antimony, which averaged 11,081 mt/jo* dur- 
ing the same period. The United States will thus continue to rely on imported ores and/or 
concentrates, antimony oxides, and metal to satisfy domestic industrial requirements. 

At production costs up to $1.15/lb Sb, 110,000 mt of refined antimony is potentially 
available from 10 of the 21 studied properties. At $2/lb, 294,000 mt Sb is available, 
and at $3/lb, the total rises to 304,000 mt Sb available from all evaluated producers 
of refined antimony. 



'Mining engineer. 

'Supervisory physical scientist. 

Minerals Availability Field Office, Bureau of Mines, Denver, CO. 



2 



INTRODUCTION 



This Bureau of Mines study provides an analysis of the 
geological, engineering, economic, eind other factors that 
influence the availability of primary antimony. A number 
of small producers in Bolivia and Mexico were not included 
in the analysis because of inadequate information concern- 
ing production and resource availability. 

Production costs of antimony metal and antimony triox- 
ide (SbjOa) are not significantly different. In this study, an- 
timony metal and SbjOj are considered the final marketable 
products. Antimony is recovered either as a primary prod- 
uct or as a byproduct of other metal, mostly at the smelter. 
Antimony as a metal is also recovered fi-om the recycling 
of scrap metal (mostly battery scrap). However, in this 
study, only those mines and deposits from which antimony 
is or can be produced as a primary product have been 
analyzed. 

Byproduct and secondary antimony were not analyzed, 
because it is not possible to track down the sources from 
which these products £u-e being recovered. Moreover, 
recovery of antimony as a byproduct is incidental to the pro- 
duction of other metals. Significant domestic antimony pro- 



duction comes fi-om silver processing to eliminate antimony 
penalty. 

Production of secondary antimony mostly is incidental 
to the recycling of other metals in which antimony is an 
alloy. Antimony is used mainly as an alloy for lead (an- 
timonial lead alloy for battery) with or without other metals. 
Therefore, the recovery of secondary antimony depends 
mainly on the extent to which lead is recycled. 

Estimate of total world antimony resources are conflict- 
ing and vary fi-om one som-ce to another. These sources are, 
however, in consensus that more than half of the total 
world's antimony resources are located in China. In 1983, 
the United States imported about 50 pet of its antimony 
metal requirements fi-om China. 

Antimony resources located in Soviet Union, China, emd 
other centrally planned economy countries (CPEC's) were 
not analyzed in this study. Production cost estimates could 
not be supported because of the difficulty in collecting quan- 
titative resource information. This study consolidates past 
work and recent information from numerous sources as of 
January 1984. Current and potential antimony availabil- 
ity data are presented in this study. 



COMMODITY OVERVIEW 



PRODUCTS AND USES 

Antimony is primarily used in its metallic form as an 
alloying element to increase strength and inhibit chemical 
corrosion, such as in antimonial lead used in lead-acid 
storage batteries. This application has been substantially 
replaced by lead-calcium maintenance-free batteries. The 
effect of lead-calcium batteries is reflected in the decline 
in the antimonial lead consumption from 6,578 mt Sb in 
1974 to 766 mt Sb in 1984 (table 1). However, recent find- 



ings show that lead-calcium batteries have a shorter life 
than those using antimony. The Battery Council Interna- 
tional in Chicago reported in May 1982, that the average 
life for the lead-calcium batteries had been 27.3 months com- 
pared with 36.7 months for the lead-antimony batteries (1).^ 
This may allow antimony-alloyed battery grids to regain 
part of the battery market (2). Any recovery is expected to 
remain small and probably will not attain the consumption 

'Italic numbers in parentheses refer to items in the Hst of references at 
the end of this report. 



Table 1.— Reported industrial consumption of primary antimony in the United States by end use, 1974-84 

(Metric tons contained antimony) 

1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 
Metal products: 

Ammunition 110 217 57 125 121 229 328 371 267 159 

Antimoniallead 6,578 4,144 3,502 2,663 2,569 1,179 678 1,140 719 840 

Bearing metals and bearings 432 365 367 240 253 213 202 187 130 130 

Cable covering 15 21 17 15 19 15 28 22 23 28 

Castings 28 16 22 12 13 13 9 10 8 8 

Collapsible tubes and foil 16 8 21 15 15 22 16 8 1 W 

Sheet and pipe 63 54 67 51 35 33 26 33 24 39 

Solder 186 121 171 200 187 180 122 95 112 140 

Type metal 97 68 72 75 73 34 19 17 10 9 

Other 122 109 149 94 102 90 67 63 61 64_ 

Total 7,647 5,123 4,445 3,490 3,387 2,008 1,496 1,946 1,355 1,417 

Nonmetal products: 

Ammunition primers 10 13 12 12 12 21 18 23 18 15 

Ceramics and glass ,.. 1,256 897 1,143 1,403 1,142 1,022 1,182 709 1,232 1,136 

Fireworks 10 9 11 8 4 5 3 3 5 4 

Pigments 417 291 376 363 372 362 453 309 299 180 

Plastics 1,298 990 1,158 1,363 1,321 1,433 1,484 1,407 952 901 

Rubber products 602 415 524 429 230 165 295 210 200 63 

Other 1,150 596 1,206 241 150 126 97 101 94 108 

Fire retardants 3,976 3,446 5,036 5,230 5,310 5,517 5,166 5,806 4,383 5,628 

Total 8,719 6.657 9,466 9,049 8,541 8,651 8,698 8,568 7,183 3,035 

W Withheld to avoid disclosing proprietary data; included with "Other." 



1984 



W 

766 

153 

W 

10 

W 

73 

207 

28 

306 



1,543 



19 

1,172 

6 

161 

1,005 

19 

145 

7,219 



9,746 



level of 1974, since the antimony content used in antimony- 
lead batteries had been dropping; e.g., in 1972 antimonial 
lead batteries used 6 pet Sb, but in 1977 the antimony con- 
tent dropped to 4 pet (1). Lead-antimony alloy also finds in- 
dustrial use in tank linings, chemical pumps and pipes, roof- 
ing sheets, and cable sheaths. When alloyed with tin, an- 
timony forms hard crystals that increase bearing life. In 
general, antimony is added to other metals or alloys to in- 
crease hardness, reduce shrinkage, and promote sharp 
definition in castings. 

The nonmetallic consumption of antimony, the larger 
portion of the total consumption, is primarily in fl£une retar- 
dants. SbjOs, the most commonly used antimony compound 
in the manufacture of flame retardant, is not a fire retar- 
dant per se. However, when combined with halogens such 
as chlorine and bromine, a synergistic reaction occiu"s and 
the resulting halogenated nuxtures become a very effective 
fire retardant. At this time, no satisfactory theory has yet 
been advanced to explain the synergistic effect of halogens 
and SbjOg as flame retardants. 

Other antimony compounds used in the manufacture 
of flame retardants are antimony pentoxide (SbjOs) and 
sodium antimonate (NaSbOj). Both are products of oxida- 
tion of SbjOs. SbzOs, because of its lower opacity, is exten- 
sively used in textile industry, while NaSbOj, because of 
its higher opacity, is used in products with dark color. 

Information in table 1 shows the use of antimony com- 
pounds in fire retardant applications is high. Other an- 
timony compounds used in the industry include antimony 
pentasulfide (SbjSs), used as vulcanizing agent; antimony 
trisulfide (SbjSg), used as primer in ammunition and as 
smoke markers; and antimony trichloride (SbCla), used as 
medicine and a catalyst. 



SUBSTITUTES 

In recent years, the use of antimonial lead in the United 
States declined sharply owing to the introduction of the 
lead-calciiun battery grids in maintenance-free batteries. 
In the United Kingdom, and probably other Western Euro- 
pean countries, the change from lead-antimony to lead- 
calcium has not progressed. This is because of the different 
production techniques used in each country. Battery grids 
manufactured in the United States are produced by expand- 
ing and pressing methods, while in the United Kingdom, 
the grids are produced by castings. Lead-calcium alloys are 
not amenable to casting techniques. 

' Antimony had been used as an opacifier for enamel and 
pigments for paints and lacquers. Titanium, zirconium, 
lead, zinc, chromium, and tin may be substituted for this 



application. As a hardening agent for lead, antimony can 
be replaced by tin, calcium, cadmium, seleniiun, and sulfur. 
Selected organic compounds and aluminum oxides are 
widely accepted alternative materials in flameproofing. 
Plastic and alimiinum are gaining acceptance as cheap 
substitutes for cable sheathings. 



U.S. PRODUCTION, CONSUMPTION, AND TRADE 

U.S. production, consumption, and trade of primary an- 
timony (1975-84) Eire shown in table 2. Primary domestic 
antimony production is from Stibnite Hill (Babbitt) Mine 
in Montana. The Sunshine Mine in Idaho, although produc- 
ing a larger tonnage than Stibnite Hill Mine, was not 
analyzed, because the antimony produced in this mine is 
a b3T)roduct of its silver recovery. Antimony bs^jroduct pro- 
duced in domestic lead smelters has no definable resource 
base. In addition, the smelter feed is generally from a 
number of mines (both domestic and foreign); thus, the an- 
timony cannot be identified with any particular resource 
base. Any analysis of byproduct antimony, therefore, would 
be erroneous. 

Reported domestic consumption of primary antimony 
averaged 11,081 mt/yr of contained antimony over the 10-yr 
period (table 2). The consumption of primeiry antimony has 
declined in recent years, primarily due to the reduced 
amount of antimonial lead consumption in automotive bat- 
teries. On the other hand, the use of SbaOs in flame retar- 
dant applications has been increasing and expanding 
especially in plastic, textile, rubber, and pigment products. 
This increase is expected to offset the decline in use ex- 
perienced in the battery industry. 

Since there are no significant changes foreseen in the 
mining of domestic antimony, the United States will con- 
tinue to depend on foreign sources for antimony ores, con- 
centrates, oxides, and metal. Currently, the United States 
imports about 95 pet of the total industrial requirements, 
mostly from Bolivia, Mexico, South Africa, and China (3). 
The United States exports insignificant amounts of an- 
timony metal, alloys, and scrap, averaging only 443 mt/yr 
contained Sb over the last 10-yr period. 

MARKET STRUCTURE 

Antimony is sold as ores, concentrates, metals, triox- 
ides, and to a minor extent, as antimony products such as 
antimonial lead, SbjSs, and other compounds. Among 
MEC's, South Africa and Bolivia are the major suppliers 
not only of ores and concentrates but also of metals and 
trioxides. 



Table 2.— Salient antimony statistics, 1975-84 

(Metric tons contained antimony) 

1975 1976 1977 1978 1979 ~ 

United States: 

Primary production: 

Mine 803 257 553 724 655 

Smelter 11,056 13,259 11,634 12,798 13,662 

Secondary production 16,294 17,958 27,756 23,996 21 ,909 

Export of metal and alloys 308 309 673 504 440 

Import for consumption (antimony content) .. . 16,967 19,746 12,095 15,882 20,083 

Reported consumption, primary antimony' ... 11,780 13,911 12,539 11,929 10,660 
Stocks: Primary antimony, all 

classes (antimony content), Dec. 31 13,566 13,669 7,792 7,439 6,480 

World production 69,945 64,762 67,676 61 ,897 63,056 

^Preliminary. 

'Includes primary antimony content of antimonial lead refineries. 



1980 



1981 



1982 



1983 



1984P 



311 



586 



456 



760 



505 



14,569 


16,185 


11,140 


13,206 


15,403 


18,044 


18,010 


15,053 


12,883 


14,432 


411 


294 


753 


276 


463 


16,323 


16,299 


12,142 


11,687 


20,942 


10,194 


10,514 


8,539 


9,450 


11,289 


7,629 


8,307 


5,418 


3,569 


6,273 


63,510 


57,584 


53,766 


50,372 


53,394 



Table 3 identifies the major sovirces of antimony pro- 
duction capacity by product type. Total antimony produc- 
tion capacity in all forms is estimated at 61,500 mt. Bolivia, 
the l£u*gest producer of ores and concentrates, oxides, and 
metal, has a capacity of about 15,500 mt/5rr of ore and con- 
centrates, 5,000 mt/jT of metal, and 1,000 mt/3T SbaOg. 
South AfHca produces about 13,500 mt/srr of ore and con- 
centrates and 6,000 mt/3rr of crude antimony trioxide with 
a purity of 81 to 83 pet SbjOg, although a purer form grading 
about 97 pet SbjOg is also being produced (2). 

Table 3.— Estimated antimony annual production capacities 

(Metric tons contained antimony) 



Trioxide Metal 





1,000 







6,000 

BOO 

1500 





5,000 



800 







1400 



8,300 



6,200 



Ore and 
concentrates 

Australia 1 ,200 

Bolivia 15,500 

Canada 5,900 

Mexico 3,700 

Morocco 4,700 

Republic of South Africa 13,500 

Turkey 2,500 

United States 

Total 47,000 

1 Production may be consumed internally. 



PRICE STRUCTURE 

There is no specific antimony price structure in the in- 
ternational market. Actual prices are normally calculated 
by means of an agreed-upon formula between seller and 
buyer. The formula is based on the quality and form of the 
product sold. Published prices in trade journals £ire price 
ranges, which include not only the producer's price and 
dealer's price but also the assessed price for certain stan- 
dard products based on the product information furnished 
by buyers and sellers (i). Occasionally the publication of 
a specific product price is suspended because information 
is insufficient to base an adequate assessment. 

Ores and concentrates, the basic marketable antimony 
products, are sold in metric ton units of contained antimony. 
In recent years, the vertical integration of two major pro- 
ducing countries (Bolivia and the Republic of South Afi-ica) 



has weakened the international trade in antimony concen- 
trate. Trade journals suspended publishing prices for 50 to 
55 pet Sb in concentrate in December 1976, although the 
prices for 60 pet Sb in sulfide ore are continued. Table 4 
reflects concentrate price in international trade. 

Table 4.— U.S. antimony prices, 1975-84 



Year 


Metal, 


S/lb^ 


Oxide, $/lb 
High Low 


Sulfide concentrate 
(55 pet Sb), $/nitu 


Lump sulfide ore 


High Low 


Average 


(60pctSb),$/mtu 


1975. 


. 2.23 1.58 


1.77 


2.16 1.65 


17.50-20.00 


20.25-22.75 


1976. 


. 1.75 1.58 


1.65 


1.80 1.65 


20.50-22.30 


23.70-25.25 


1977. 


. 1.78 1.75 


1.78 


1.80 1.64 


NA 


18.87-22.00 


1978. 


. 1.35 1.05 


1.14 


1.80 1.64 


NA 


16.92-18.07 


1979. 


. 1.60 1.25 


1.41 


1.80 1.50 


NA 


21.04-22.39 


1980. 


. 1.65 1.45 


1.51 


1.80 1.50 


NA 


23.50-25.00 


1981. 


. 1.52 1.20 


1.36 


1.80 1.40 


NA 


20.50-22.50 


1982. 


. 1.24 .93 


1.07 


1.80 1.20 


NA 


17.81-18.63 


1983. 


. 1.35 .78 


.91 


1.20 1.00 


NA 


16.75-17.25 


1984. 


. 1.77 1.20 


1.51 


1.80 1.16 


NA 


18.25-19.00 



NA Not available. 

ipor years 1975-77 domestic producer price to RMM brand 99.5 pet Sb metal 
f.o.b. Laredo, TX. For years 1978-84, New York dealer price for 99.5 pet to 
99.6 pet imported metal, c.i.f. U.S. port. 

Sources: American Metal Market; Chemical Marketing Reporter; Metals 
Week; Metal Bulletin. 

Antimony oxide prices published in trade journals have 
a wider range, partly because they include prices set by 
ASARCO, which are normally at the lower end of the range. 
The probable reason why ASARCO can maintain a com- 
petitive price is the fact that antimony produced by the com- 
pany is only incidental to its lead smelting operation. Hence, 
most of its operating cost is tied to the lead recovery rather 
than to antimony. These antimony oxide price ranges are 
further complicated by the quality of specific oxided prod- 
ucts; e.g., high-tint oxide costs less than low-tint oxide, while 
ultrapure oxide costs about $0.22/kg more than low-tint 
oxide. 

Antimony metal price is quoted in several different 
ways. Aside from the producer's and dealer's prices, jour- 
nals publish market prices for both the United States and 
the western European countries. Prices for these countries 
Eire expressed in terms of U.S. dollars per pound. Prices for 
Japan, on the other hand, are expressed in terms of yen per 
kilogram. The European market price generally is lower 
than the New York dealer's price. 



GEOLOGY 



Antimony distribution ranges from 0.2 to 0.5 ppm in 
the continental crust. In igneous rocks, the concentration 
ranges fi-om 0.1 to 1.0 ppm with higher concentration noted 
in basaltic than in granitic rocks (4). Because of its strong 
affinity for sulfur and the metallic elements such as lead, 
copper, and silver, antimony is rarely found as native metal. 

Normally associated with igneous activity, antimony 
deposits are genetically related to such intrusives as 
granites, diorites, and monzonites. Antimony ores are com- 
monly found in quartzose veins, in pegmatites, and as 
replacements in limestone. Typical antimony deposits are 
small, irregular, and discontinuous bodies with grade 
sharply decreasing at depth. The geology of each primary 
antimony properties that were studied is discussed below. 



DEPOSIT GEOLOGY 
Australia 
Hillgrove Mine 

The Hillgrove Mine is located in northern New South 
Wales. The property has geographic coordinates of latitude 
30°34'30" S. and longitude 151°54'30" E. 

Stibnite mineralization occurs in low-temperature 
hydrothermal veins with quartz and calcite. The antimony 
occvtrrences are grouped into antimony, antimony-scheelite, 
and antimony -gold deposits. Some of the lode deposits are 
emplaced along granite dykes, though most are in 



metasediments. The width of the lodes range from a few 
centimeters to a meter. 

The principal antimony mineral is stibnite. Some of the 
associated minerals are pyrite-pjTrhotite, arsenopyrite, 
scheelite, graphite, and gold. 

Effective mining operations in the area started in 1972 
after Vam Ltd. acquired the property. To increase the ore 
resovirces, Vam Ltd. secured an agreement with Silver 
Valley Mineral N.L. to mine the Hillgrove area. From 1971 
to 1976, the main mining activity was centered on Smith's, 
Freehold, and Garibaldi lodes, but in 1977 the operation 
was shifted and limited to the richer and more accessible 
Freehold Mine, because of the slump in antimony prices. 

Wild Cattle Creek Mine 

The Wild Cattle Creek Mine is also located in New 
South Wales. The geographic coordinates are 30° 13 '30" S. 
and longitude 151°43'30" E. 

The antimony deposit lies within a sedimentary succes- 
sion known as Fitzroy beds and consists of interbedded 
phyllites and metaquartzites. Regional metamorphism 
formed a strong foliation, which obliterated most traces of 
the original bedding. The deposit is situated near the center 
of a main shear zone. The best known antimony mineraliza- 
tion occurs in a lode having a strike length of about 335 
m, a width of up to 14 m, and variable thickness from 2 
m to 15 m. Stibnite mineralization has been found in minor 
quantities both east and west of the main deposit in sub- 
parallel shear zones with a total length of 5.5 km. Stibnite, 
the principal ore mineral, occurs with minor cinnabar, 
pyrite, and. arsenopyrite. 

Antimony was mined in the area from 1890 to 1892. 
Since then, several shafts were sunk and trenching was 
done, but due to low antimony price and high freight cost, 
the mining operation was not successful. In 1970, 
Australian Antimony NL acquired the ownership and 
brought the property into production in 1973; in 1977, 
however, it closed the mine operation and placed it under 
care and maintenance. 



Bolivia 



Candelaria Mine 



Candelaria Mine is located in the southern part of 
Bolivia. The geographic coordinates are latitude 21 °33'00" 
S. and longitude 66°07'00" W. 

The Candelaria deposit occurs in shale, sandstone, and 
quartzite that has been folded into an anticline and 
sjmcline. Antimony is concentrated along the flanks and 
axis of the folds. The zone of mineralization is approxi- 
mately 2,000 m long, 500 m wide, and has a variable width 
of a few centimeters to more than 1 m. 

Discovered in the 1930's, the mine has been worked 
from time to time since 1945. Intermittent production oc- 
curred until 1970, when semimechanization was introduced. 
Since then, Empresa Minera San Juan Ltda. has operated 
the mine without interruption. 

Caracota Mine 

The Caracota Mine is located in the southern part of 
Bolivia. The geographic coordinates are latitude 20° 05 '00" 
S. and longitude 65°55'00" W. 



The rocks consist of a series of slates, sandstones, quartz- 
ites, and schists. The strata have been folded into a series 
of anticlines and synclines. The most favorable mineral zone 
is the contact zone of the intercalated quartzite and shale. 
The major mineral zone has a strike length of 200 m, a 
width of 150 m, and a variable thickness that can exceed 
3 m. 

The principal ore mineral is stibnite, which is associated 
with quartz, p3Tite, and arsenopyrite. Another accessory 
mineral is galena, which occurs in larger quantities at 
depth. The quantity of galena is insufficient for economic 
recovery and hinders antimony recovery. Gold is also found 
in some antimony veins. 

Discovered before 1900, the mine was never extensively 
developed because of low antimony demand. Mining ac- 
tivities increased toward the end of World War 11. Empresa 
Minera Unificada S.A. (EMUSA) acquired the mine in 1946 
and mechanized the operation in 1965. 

Chilcobija Mine 

Chilcobija Mine is situated in the southern section of 
Bolivia. The approximate geographic coordinates are lati- 
tude 21°24'00" S. and longitude 66°06'00" W. 

The deposit is related to a series of folds in a sym- 
metrical anticline. Antimony vein structures formed in both 
flanks of the anticline, with the eastern flank more in- 
tensely mineralized. The predominant rock in the area is 
a sequence of laminated black shales intercalated with 
quartzite. 

The primary ore forming mineral is stibnite, which is 
associated with small amounts of pjrrite and quartz. The 
zone of mineralization has a length of 150 m, a width of 
60 m, and a thickness varying from a few centimeters to 
3 m. The mineralized zone contains an estimated in situ 
demonstrated resource of 376,300 mt averaging 4.77 pet Sb. 
An additional inferred resource of 284,900 mt, averaging 
2.84 pet Sb, is indicated in the area. 

Discovered in the early 1900's, the deposit was mined 
in a small and primitive way. After World War 11, large- 
scale mining was initiated by EMUSA. Mechanization was 
introduced in 1960, and operation has continued without 
interruption since 1974. 

Churquini Mine 

Churquini Mine is located in southern Bolivia. The 
geographic coordinates are latitude 21°05'00" S. and 
longitude 65°57'00" W. 

The area that comprises the Churquini property is on 
an anticlinal structure. Tectonic movements opened up ma- 
jor and minor fissures along, as well as transverse to, the 
anticlinal axis where subsequent antimony mineralization 
took place. Four types of ore deposits are found: (a) ore 
pockets along the axis, (b) small lenses intercalated with 
slate found along the crest, (c) ore deposits found along the 
flanks of the anticline, and (d) ore deposits along fractures. 
The mineralized zone has a length of 1,500 m and an 
average width of 40 m, and extends in depth to over 200 
m. It is estimated that the zone contains a demonstrated 
resource grading 3.96 pet Sb. 

Records show that the deposit has been worked since 
1908 on a small scale. Santiago White acquired the prop- 
erty in 1930; he later sold the stocks to Cia. Metal Traders 
Overseas, who foiuided the Empresa Churquini Enterprises 
Inc. Anschutz Mining Corp., a U.S. company, bought the 
mine in 1979 but retained the name Chm-quini Enterprises 
Inc. 



Espiritu Santo Mine 



Canada 



Espiritu Santo Mine is located in the southern part of 
Bolivia. The geographic coordinates are latitude 16°55'00" 
S. and longitude 67°48'00" E. 

The Espiritu Santo deposit occurs in dark slippery 
mudstones and lies along the axis of a plunging anticline. 
The antimony occurs in two rock formations: the "Carne 
de Vaca," which is a compact mass of crystalline aggregates, 
and the "Acerada," which consists of fine, compact crystals. 
The zone of mineralization is composed of one primary and 
two secondary veins with a strike length of approximately 
150 m, a width of 50 m, and variable thickness of up to 2 
m. The antimony minerals occur as stibnite with psrrite, 
arsenopjT-ite, quartzite, and siderite as associated minerals. 

The deposit was discovered in the 1920's and was 
worked in a small, primitive way from 1928 to 1957. In 1957 
EMUSA acquired the property and mined it intermittently 
until 1970, when the operation was mechanized. Produc- 
tion continued without interruption from 1979 until 1982, 
when the mine was placed under care and maintenance. 

La Salvadora Mine 

The La Salvadora Mine is located in the central part 
of Bolivia. The geographic coordinates are latitude 
17°30'00" S. and longitude 66°55'00" W. 

Antimony minerals occur in quartz veins contained in 
micaceous black lutite. The quartz veins are observed and 
restricted to the "La Salvadora" fault. The zone of 
mineralization has a length of 300 m, a width of 50 m, and 
variable thickness of up to 0.5 m. The zone contained a 
demonstrated in situ resource of 58,998 mt in 1984. The 
principal veins, the San Juliano and the Progresso, are frac- 
tured mineral zones contained in lutite. 

The principal ore mineral is stibnite, which is associated 
with quartz, pyrite, and arsenopyrite. The deposit was 
discovered in 1968 and was worked until January 1980, 
when the property was sold to Churquini Enterprises Inc. 



Rosa de Oro Mine 

Rosa de Oro Mine is located in the southern part of 
Bolivia. The geographic coordinates are latitude 21 °41 '00" 
S. and longitude 66°07'00" W. 

The deposit occurs in sandstone, quartzite, and inter- 
calated slate that have been folded into an anticline. The 
principal structure has a length of 3 km. Vein thicknesses 
vary from a few centimeters to 4 m. Near the surface level, 
lenses of ore can be observed, but at depth veins occur in 
irregular shapes. The principal ore lens at Rosa de Oro has 
a length of 75 m, a variablfe width of up to 4 m, and an 
average grade of 2.5 pet Sb. 

The ore forming mineral is stibnite in association with 
quartz and pyrite. In some mineral zones, the stibnite has 
replaced the slate resulting in high antimony values. The 
deposit has a length of 100 m, a width of 35 m, and a 
variable thickness ranging up to 4 m. Additional inferred 
resources having an average grade of 2.5 pet Sb have been 
reported in the area. 

The deposit was discovered at the tvirn of the century, 
and has been worked since 1905 in a small and primitive 
way. The original owners formed the current Empresa 
Minera Bernal Hermanos in the early 1970's, and opera- 
tions have continued since 1976 without interruption. 



Lalce George Mine 

Lake George Mine is located west of Fredericton, NB. 
Its approximate latitude is 45°52'00" N. and its longitude 
67°02'00" W. 

The antimony deposit lies southeast of the Hackshaw 
intrusion. Hydrothermal alteration effects were observed 
along numerous northerly and easterly trending fractures 
within the intnision. Antimony veins occupy fractiu"e zones 
that trend easterly and occur as lens-shaped bodies irregu- 
larly distributed throughout the zones. The dimensions of 
the irregular mineralized structvires are approximately 
1,250 m long, 550 m wide, and 550 m deep. The deposit is 
still open at depth. Diamond driling to a depth of about 550 
m vertically indicates the vein structvu-e continues into a 
siliceous skarn zone about 120 m thick. The zone contains 
abundant quartz stringers with stibnite and chalcopyrite 
blebs. 

The main ore-forming minerals are stibnite and native 
antimony. Stibnite occurs in the eastern part of the deposit, 
whereas native antimony predominates in the western part 
of the deposit. Some native antimony is associated with 
uranium minerals. Tetrahedrite containing small ex- 
solution blebs of chalcopyrite is present in small amounts. 
The most abundant metallic gangue minerals in the mine 
are arsenopyrite, pyrite, and pyrrhotite. Quartz and car- 
bonates constitute the most abundant nonmetallic minerals. 

Antimony was discovered in the Lake George area about 
1863. The first recorded mine production occvirred in 1880 
and continued intermittently until 1890, when all opera- 
tions were suspended. Between 1906 and 1970, sporadic 
mining operations would start up but would close shortly 
thereafter because of recurring arsenic problems and low 
antimony prices. 

Consolidated Durham Mines & Resources Ltd. started 
a new mining initiative by exploring the area in 1970. Pro- 
duction began in 1971 at 180 mt/d ore. After a 6-month shut- 
down in 1972, operations were resumed until 1981, when 
low demand and poor metal prices once more forced its 
closure. The mine is presently under care and maintenance. 
It is quite likely that additional resources could be found 
in the area. 



Italy 



Manciano Mine 



The Manciano Mine, one of the antimony mining units 
of Societa per Azioni Minero-Metallurgiche (SAMIM) located 
in the Tuscany district, has a geographic location at about 
latitude 42°48'00" N. and longitude 11°15'00" E. 

Ore deposits in the area are genetically related to 
magmatic activity. Postvolcanic manifestations such as 
steam jets and thermal springs are still active. The anti- 
mony minerals consist of stibnite in quartz bodies and are 
found at the contact between limestone and Tertiary sand- 
stone. Structurally, the ore is localized by faults developed 
after the area was folded. 

The only ore mineral found in quantity is stibnite; oc- 
casionally, some weathering products, oxides, hydroxides, 
hydrous calcium antimonates, and oxysulfides are found. 
The gangue mineral is mainly quartz, sometimes accom- 
panied by traces of barite and fluorite. Ubiquitous calcite 



and dolomite were derived from the country rock. Abun- 
dant gypsum is believed to be the product of supergene 
enrichment. 

Antimony production in the Tuscany district started in 
the early part of the 19th century, but production ceased 
in the middle of the century. Records concerning early pro- 
duction are sparse Jind incomplete. Production resumed dur- 
ing both world wars and has been active since World War 11. 

Following World War 11, the mining units were con- 
trolled by the AMMI Industrial Group. Exploration work 
by the company in 1950 led to the discovery of a new ore 
horizon. AMMI was a member of the EGAM Group, the 
state-controlled minerals agency that was abolished in 1978 
under the same law that created SAMIM, the present 
operator. 



Mexico 



Wadley Mine 



The Wadley Mine is located in the western section of 
La Sierra de Catorce in the State of San Luis Potosi. The 
approximate geographic coordinates of the mine are latitude 
23° 39 '00" N. and longitude 100°49'00" W. 

The stratigraphic sequence is represented by formations 
that have been identified in other locations. The older and 
more voluminous formation is the Zuloaga's calcareous bed, 
followed by the La Caja formation, both of which are from 
the Upper Jurassic period. The alluvivmi and conglomerate, 
the most recent deposits, are located in the eastern part of 
the area. 

The important stratigraphic ore controls in concen- 
trating the mineral are the permeability and the chemical 
reactivity of the host rock, which permit the circulation of 
solutions and precipitation of antimony minerals. The 
deposits, particularly the Wadley deposit, are believed to 
have formed from ascending hydrothermal solutions of 
magmatic origin. 

The main ore-forming minerals are stibnite and cervan- 
tite (stibiconite). Gangue minerals are quartz, barite, 
fluorite, and calcite. Stibnite generally occurs in coarse- 
grained crystals. The ore deposits are in a series of lenses 
and as such have irregular proportions and indefinite 
dimensions. 

Antimony was discovered in La Sierra de Catorce 
district in 1892. Since then, the area had been mined on 
and off for the last 92 yr. In 1969, the property leases and 
mine facilities were acquired by Cia. Minera y Refinadora 
Mexicana S.A. from NL Industries, Inc. 



Morocco 
Timerhdoudine Mine 

Timerhdoudine Mine is located in the northeastern part 
of Kef-N'Soiu- mining district in central Morocco. The prop- 
erty has geographic coordinates of approximately latitude 
32°59'00" N. and longitude 5°59'00" E. 

The Kef-N'Sour mining district consists of highly folded, 
fractiu-ed, and faulted basement rocks of quartzite and 
schists. A fault bounding the block of the basement rock 
appears to be highly mineralized, especially where it is ac- 
companied by quartzite. Two ore zones were identified in 
the area: Timerhdoudine No. 1 lode, measuring about 220 
m long^nd 60 jn wide, and Timerhdo udine No. 2 lode . 



measuring about 320 m long and 30 m wide. Mineral 
deposits within the two lodes occur at varying depths from 
about 50 m to 110 m below the surface with an average 
thickness of 60 m. The principal antimony mineral is stib- 
nite with minor association of pyrite, barite, and quartz. 
The Timerhdoudine deposit was discovered in 1960. 
Mining started on a small scale in 1973 and continued ex- 
panding to a production rate of 2,000 mt/yr. Based on a drill- 
ing progreim underteiken in 1981, a feasibility study recom- 
mends to expand the production capacity to 40,000 mt/yr 
starting in 1984. 

Tourtit Mine 

The Tourtit Mine is in the Atlas Mountain region of cen- 
tral Morocco with approximate geographic coordinates of 
latitude 32°29'00" N. and longitude 5°50'00" E. The region 
is underlain by silicified schists that were folded, fractured, 
and later faulted. Subsequent mineralization took place and 
formed a stockwork type of deposit. The ore deposit consists 
of a near-vertical slab. 

The deposit measvu*es about 300 m in length, has an 
average width of 12 m, and extends vertically some 150 m. 
The principal antimony mineral is stibnite, with minor 
associations of galena, pyrite, and quartz. 

The antimony deposit was discovered as a result of a 
lead-zinc district discovery in 1960. Initial works consisted 
of a small-scale operation begun in 1978. Presently, the 
mine is under care and maintenance due to the depressed 
antimony metal price. Exploration work, which has con- 
tinued at a modest rate since the mine was placed into pro- 
duction, has delineated substantial additional resources. A 
feasibility study done by a Yugoslavian engineering com- 
pany showed that the mine should expand to a production 
level of 60,000 mt/yr ore. 

Republic of South Africa 

Consolidated Murchison Ltd. Mines 

The Consolidated Murchison Ltd. (CML) antimony 
mines are located in the Letaba district of the northeastern 
Transvaal. The approximate geographic coordinates of the 
mines are latitude 24°00'00" S. and longitude 31°31'00" 
E. The antimony -producing mines are in the Murchison 
Range, a belt of sedimentary and carbonate rocks about 130 
km long and 20 km wide. Antimony minerals are sparsely 
distributed along a shear zone. Local concentrations occur 
in fissures associated with vertical dragfolds. 

The antimony mineral is mainly stibnite and some 
berthierite, which are considered medium-temperature 
hydrothermal minerals. The mineral zone also carries gold, 
cinnabar, and tetrahedrite. Though mineralization is not 
continuous, economically exploitable deposits are largely 
concentrated in a strike length of 13 km along the southern 
limb of a syncline. 

Antimony mining in the area started during World War 
I. Unsuccessful recovery of the element by means of a li- 
quation and leaching process caused production to cease 
soon after. In 1928, recovery of antimony was considered 
worthwhile as a b5T)roduct of gold production. Since then, 
antimony production was slowly increased, and in 1943 an- 
timony concentrate became the major product. 

Antimony deposits in the area are unusually extensive 
by world standards. It is estimated that the ore zone will 
be productive for many years. 



Thailand 



Bo Thong Mine 



Bo Thong Mine is located in the Chonbvtri Province. The 
deposit has geographic coordinates of latitude 13°11'00" 
N. and longitude 101°41'00" E. and is at an elevation of 
100 m above sea level. 

The general area consists of slightly metamorphosed 
Paleozoic rocks. Outcrops in the vicinity of the antimony 
deposit consist of sandstone, quartzite, and carboniferous 
shale striking northeast-southwest. The mineral zone is 
about 1,000 m long, 200 m wide, and 1 m thick. The deposit 
is composed of fragments and boulders of stibiconite, quartz, 
chalcedony, sandstone, and shale. The primary mineral is 
stibiconite with minor amounts of stibnite. 

The deposit was discovered in 1977 along the border be- 
tween Chonburi-Rayong and Chanthaburi-Chachoengsao 
Provinces. Detailed geological mapping and geochemical ex- 
ploration sxirveys undertaken by the Thailand Department 
of Mineral Resoiirces indicated extensive antimony 
■mineralization along a belt 60 km long and 30 km wide. 
Weak market conditions for antimony metals caused ex- 
ploration drilling on several anomalies to be postponed. 

Dol Ngoem IMine 

Doi Ngoem Mine (Ban Pin Antimony Mine) is located 
5 km north of Ban Pin Phrae Province. The property has 
geographic coordinates of latitude 18°08'00" N. and 
longitude 99°51'00" E. at an elevation of 250 m above sea 
level. 

The area is underlain by Permian to Triassic sedimen- 
tary rocks and by intrusive and extrusive igneous rocks. 
The Permian rocks, consisting of shale, sandstone, and con- 
glomerate, are found in the eastern part of the area; the 
Triassic rocks, consisting of a volcanic series and composed 
of andesite, rhyolite, and agglomerate, are found in the 
western part. The antimony mineral occurs in quartz veins 
along breccia zones of quartzite and shale. The primary 
mineral is stibnite accompanied by significant amounts of 
arsenopjrrite. 

The ore zone is 100 m long and 15 m wide and extends 
approximately 50 m downward. The first mining lease in 
the area was initiated in 1974. At the time, mining was 
limited to exposed ore. The area has a high potential of ad- 
ditional antimony resource, but no systematic exploration 
has been conducted. The Thailand Department of Mineral 
Resources performed a detailed geological mapping and 
geochemical exploration; the anomalies discovered have yet 
to be drilled. 

l\/lae Ta l\Aine 

i 
i 

The Mae Ta (Mae Tha) Mine is located in Tambol Mae 
Ta Luang, Amphoe Chae Hom district, in the northern part 
of Lampang Province. The geographic coordinates are 
latitude 18°45'00" N. and longitude 99°38'00" E. at an 
elevation of 400 m above sea level. 

The antimony deposits lie in a massive Permian 
limestone interbedded with shale, calcareous shale, and thin 
layers of sandstone and chert. The deposit occurs as veins 
in brecciated sediment layers, in large limestone pockets, 
or in disseminated bodies at or near limestone contact. The 
major ore minerals are stibnite and stibiconite. Exploration 
work in the area has been limited to siuface outcrops. 



Records of mining operations in the area are very 
limited. It has been reported that mining activity had been 
going on for many years on an intermittent basis. Since 
1982 the mine is on care and maintenance due to depressed 
antimony metal prices. 



Turicey 



Turhal-Tolcat IMines 



The Turhal-Tokat Mines are located in central Anatolia 
Moxintains of Turkey with approximate geographic coor- 
dinates of latitude 40°00'00" N. and longitude 36°00'00" 
E. The area is part of the metamorphosed Paleozoic schist 
zone of the northern Anatolia Mountains. 

The main antimony ore vein strikes north-south, is 
about 1.5 km long, and has a variable thickness averaging 
about 2.0 m. The vein is cut by a large fault in the north. 
In the south, the vein disappears only to reappear about 
1.5 km farther south, where it is also mined. The lower zone 
of the deposit contains large amoimts of broken graphitic 
slate, which makes the antimony difficult and expensive 
to recover. The monominerallic vein indicates it was formed 
in a low-temperature environment. 

An old mine drift and smelter, supposedly used by the 
Germans prior to World War I, indicates early mining ac- 
tivity. The mining rights to the area were given to Mr. 
Ragip Ozdemiroglu in 1933, who developed the property to 
the present state. Currently, there are six mines of which 
only three are in operation. A 200-mt/d mill, consisting of 
a preconcentration gravity circuit and a flotation section, 
was installed in 1963 with the intention of replacing the 
reverberatory smelter furnace; but it was finally decided 
to continue the production of antimony metal as well as 
concentrate. 



United States 



Stibnite Hill Mine 



The Stibnite Hill Mine is in the Burns mining district, 
Sanders County, MT. The district is underlain by a unit 
of the Precambrian Belt consisting of the Missoula, the 
Piegan, and Ravalli Groups. The antimony-tungsten 
minerals are restricted to the rocks of the Prichard Forma- 
tion of the Ravalli Group. The deposits are localized along 
numerous bedding plane fractiu-es formed during Precam- 
brian folding. Four distinct types of ore mineral occurrences 
have been identified with antimony as the most common 
metallic element. Secondary minerals as products of oxida- 
tion are kermesite, valentinite, cervantite, and stibiconite. 

The antimony ore occurrence is predominantly con- 
trolled by thrust faulting that developed on the westward- 
dipping flanks of gently rolling folds. The veins have a 
thickness ranging from about 0.15 to 1.5 m. This erratic 
vein thickness contributes considerable mining dilution, 
caiising a great downgrading of the ore value. Based on a 
1.5-m mining width, the demonstrated ore resource in 1981 
was estimated to contain an average of 3.59 pet Sb and 0.392 
pet WO3. 

Stibnite was discovered in the Bums mining district in 
1884, when the area was used as a route to Coeur d'Alene 
and the gold deposits in Idaho. Mine production was 
minimal through the turn of the century. The mine was 
idled soon after. Higher metal prices during World War 11 
gave a new incentive for the development and production 
of antimony ore. The mine was closed in 1953 and reopened 
in 1972, just to close again in 1984. 



Yellow Pine Mine 

The Yellow Pine Mine is a single irregular deposit con- 
centrated along the meadow creek shear zone in north- 
central Valley County, ID. Initial fracturing was eirtensive \ 
and preceded gold deposition. 

Gold and antimony minerals occur principally in 
veinlets, stockworks, fissure fillings, and massive lenses. 
The principal antimony mineral is stibnite. Giold appears 
to be associated with pyrite and arsenopyrite, whereas silver 
is associated with antimony. 

The antimony-rich area has the shape of a flat, upright 
funnel flaring on the surface at its widest diameter and 
tapering with depth. Gold is deposited around the antimony 
mineralization and extends down the neck of the funnel. 
The ore body as delineated is 200 m wide, 600 m long, and 
about 120 m deep. It contains a demonstrated resource of 
1.6 million mt ore with grades averaging 1.09 pet Sb, 2.9 
g/mt Au, and 18.9 g/mt Ag. 

Mining in the Meadow Creek area begem when gold was 
discovered in 1900. Mining activity at that time was not 
directed towards antimony. Antimony recovery with gold 
was initially recognized in 1929. Antimony production 
began in 1932 at a rate of 140 mt/d and peedted in 1945, 
when the mine capacity reached 1,814 mt/d. Mining opera- 
tion continued at full production until 1952 when the end 
of the Korean war weakened the antimony demand. 



MINERALOGY 

Stibnite (SbjSs) is the predominant mineral of antimony. 
In areas where stibnite is exposed, the mineral is weathered 
to various oxides of antimony such as the orthorhombic 
valentinite (SbjOs), the isometric senarmontite (SbjOs), 
stibiconite (HjSbjOg), and kermesite (2SbjS3.Sb203). 



The mineralogy of the deposits and the usually shallow , 
occurrences suggest that the minerals were precipitated 
fit)m low-temperature metal-bearing solution. Due to varied 
mineral occurrences, antimony deposits are classified into 
two genetic types: simple and complex. 

Simple antimony deposits principally consist of stibnite 
or native antimony in siliceous gangue. The minerals are 
commonly associated with some pyrite and gold and small 
amounts of other metal sulfides. The stibnite is usually ox- 
idized to one of the antimony oxide minerals. This type of 
deposit is found in Thailand, Mexico, and Bolivia. Complex 
antimony deposits usually consist of stibnite associated with 
pyrite, arsenopyrite, cinnabar, scheelite, and antimony 
sulfosalts, with varying amounts of copper, lead, and silver 
as well as the common sulfides of these metals and zinc. 
Ores of the complex deposits generally are mined primar- 
ily for lead, gold, silver, zinc, or tungsten. Deposits of this 
type are found in the United States, the Republic of South 
Africa, Australia, and Canada (4). 

Of the more than 110 different antimony minerals, only 
stibnite and its oxidized equivalents and lead ores contain- 
ing emtimony 5deld substantial commercial quantities of the 
metal. Some of the more important antimony minerals are 
listed in table 5. 

Table 5.— Antimony minerals 







Antimony 






Chemical 


content, 


Specific 


Mineral 


formula 


pet 


gravity 


Antimony, native . . . 


Sb 


100.0 


6.7 -6.8 


Cervantite 


SbaOa.SbjOs 


79.2 


4.00-8.4 


Jamesonite 


2PbS.Sb2S3 


29.8 


5.5 -6.0 


Kermesite 


aSbzSaSbaOa 


83.5 


4.5 -4.6 


Livingstonite 


HgS.aSbzSa 


55.3 


4.81 


Senarmontite 


SbzOa 


83.5 


5.2 -5.30 


Stibiconite 


HjSbzOs 


74.8 


5.1 -5.3 


Stibnite 


SbjSa 


71.7 


4.52-4.62 


Tetrahedrite 


aCuaS.SbaSa 


29.8 


4.4 -5.1 


Valentinite 


SbzOa 


83.5 


5.0 -5.76 



NOTE: Chemical formulas and specific gravities are from Dana (5). 



RESOURCES 



PRIMARY ANTIMONY 

Due to the geological characteristics of antimony 
deposits, which are small, irregular, and discontinuous 
bodies, very few deposits are blocked out far ahead of the 
mining operation. Exploration and development are usually 
limited to a working reserve of a few years to minimize the 
excessive cost of blocking ore resources. In addition, the in- 
fluence of the unstable price-market conditions of the metal 
further limits incentive to explore and develop extensive 
ore resources. Under such conditions, systematic evalua- 
tion of deposit resources is absent in most cases. Thus, con- 
siderable amounts of antimony resources are only 
speculative. 

In this study, resources are included from 21 properties 
(table 6). The approximate location of each property is shown 
in figure 1. 

Resource evaluations were performed at the demon- 
strated level as defined by the U.S. Geological Siirvey and 
the Bureau of Mines. Estimated resource tonnages ag- 
gregated by region, shown in table 7, were obtained from 
either individual company data, published data, or other 
resovirces. 



The in situ demonstrated resources under study ac- 
counted for a total of 499,600 mt of contained antimony. 
An additional 973,500 mt Sb is available from inferred 
resources, though these resources were not included in 
economic analysis. Based on the demonstrated resources, 
Africa and Latin America account for about 65 pet of the 
total contained antimony (fig. 2). On the inferred level, com- 
bined resources from Latin America and "others" account 
for 80 pet (fig. 3) of the total contained antimony. The mines 
in "others," although containing smaller in situ resource 
tonnages than mines in Latin America and Africa, account 
for more than 48 pet of the total contained antimony, 
becavise they have high-grade ore deposits. 

On a regional basis (table 7), the total recoverable an- 
timony from the demonstrated resource is estimated at 
304,000 mt, with Africa accounting for 50 pet of the total. 
North America is estimated to contain 10 pet of the total 
recoverable antimony of deposits studied. The remaining 
recoverable antimony is divided between Latin America and 
Asia-Australia at 23 p>et and 17 pet, respectively. 

The antimony resources in Australia come from two 
properties: the Hillgrove Mine and the Wild Cattle Creek i 
Mine. Since areas below the present working level are com- 



10 



pletely unexplored, additional resource potential in the 
Hillgrove Mine is highly probable. 

Eight producing mines in Latin America were 
economically evaluated— seven in Bolivia and one in 
Mexico. EMUSA, a privately held Bolivian company, 
operates three of the Bolivian mines: the Caracota, Espiritu 
Santo, and Chilcobija Mines. Churquini Enterprises Inc., 
a subsidiary of Anschutz Mineral Corp. (Denver, CO), 
operates the Churquini and Salvadora Mines. Rosa de Oro 
and Candelaria Mines are independently operated. 

The only evaluated producing mine in Mexico is the 
Wadley Mine, which has been in operation for more than 

Table 6.— Deposits selected for evaluation 



Deposit and location 



Ownership 



Mining 
Status' type2 



Australia: 

Hillgrove New England Antimony Mines NL . . P 

Wild Cattle Creek Antimony Australia NL N 



Bolivia: 

Candelaria Empresa Minera San Juan Ltd ... . P 

Caracota Empresa Minera Unificada S.A P 

(EMUSA) 

Chilcobija EMUSA P 

Churquini Churquini Enterprises Inc P 

Espiritu Santo . . . EMUSA TC 

La Salvadora . . . Churquini Enterprises Inc TC 

Rosa de Oro .... Empresa Minera Bernal Hermanos . P 



Canada: Lake George Consolidated Durham Mines & 
Resources Ltd. 



TC 



Italy: Manciano^ SAMIM S.p.A TC 

Mexico: Wadley Cia, Minera y Refinadora Mexicana P 

S.A. 

Morocco: 

Timerhdoudine . . Soc. des Travaux et de P 

Recherches Miniere 
Tourtit do TC 

South Africa, 
Republic of: 
Consolidated 

Murchison 

Ltd. 



Consolidated Murchison Ltd P 



Thailand: 

Bo Thong3 Mine Organization Co P 

Dol Ngoem^ .... Prasit Mining Co P 

Mae Ta3 P.T. Smeltering TC 

Turkey: 

Turhal-Tokat , 



Ozdemir Antimony Mine Ltd P U 

United States: 

Stibnite Hill U.S. Antimony Corp TC U 

Yellow Pine Ranchers Exploration and TC S 

Development Co. 

IN = not producing as of January 1 984; P = producing as of January 1 984; 
TC = temporarily closed. 

2S = surface; U = underground. For deposits not producing, mining type 
is proposed. 

3Not included in availability analysis. 



90 yr. Due to the continuation of a prominent geologic 
feature present in the area, the inferred and demonstrated 
resources are expected to increase. 

The total demonstrated and inferred resources from 
Latin America were estimated at 400,000 mt of contained 
antimony. The demonstrated resources accounting for 24 
pet of the total, are estimated to contain 95,500 mt Sb. 

Consolidated Durham Mines & Resources Ltd., the only 
primary antimony producer in Canada, operates the Lake 
George Mine. The property is currently closed because of 
the depressed state of the antimony market. The 
demonstrated resource at the Lake George Mine is 
estimated to contain 32,100 mt Sb, with 20,500 mt Sb con- 
sidered to be recoverable (2). 

SAMIM, a government-owned company, controls the 
Manciano antimony mining properties in Italy, which com- 
prise five mining units. The ciurent working units are the 
Montauto and the Tafone, while Salaioli and San Martino 
sul Flora are being pilot tested. Macchia Casella has a large 
resource, though the property is still considered an explored 
prospect. At present, all these units are under care and 
maintenance. 

Antimony resources in Morocco (Africa) come from two 
underground mines, the Timerhdoudine and Tourtit. Drill- 
ing programs on both properties are expected to increase 
the known current resources. 

CML of the Republic of South Africa has seven mines: 
Athens, Gravelotte, Monarch, Mulati, United Jack, Weigel, 
and Free State. CML is the second largest MEC producer 
after Bolivia. Production from these operations supplies 
almost 24 pet of the MEC annual requirements. Gold is a 
significant byproduct at these operations. 

Three mining properties were studied in Thailand, two 
operating mines and one under care and maintenance. 
Although the current resources are small, additional 
resources in the area are highly probable. Recent geological 
and geochemical siu^eys conducted in the mining areas in- 
dicated extensive mineralized areas, but exploration drill- 
ing has yet to prove the anomalies. 

Ozdemir Antimony Mines Ltd., the largest antimony 
producer in Turkey, controls the Turhal's six mining units. 
At present, only four of the mining units have resources 
on a demonstrated level; the other two are under 
exploration. 

Only two properties in the United States were 
analyzed— the Stibnite Hill and Yellow Pine Mines. 
Resoiu*ces from seven small deposits (Wild Rose, Stampede 
Lode, Antimony Peak, Quien Sabe, Fencemaker, Coeur 
d'Alene antimony mine, and Antimony Canyon) were not 
included in the analyses, since the properties are either 
mined out, have a very small resource, or have too low a 
resource grade to be economically extractable at this time. 



Africa 

Asia-Australia . 
Latin America . 
North America 



Others^ 

Total . 



Table 7. — Antimony resources 

(Metric tons) 





In situ 




Estimated 
recoverable antimony 


Location 


Resources 


Contained antimony 




Demonstrated Inferred 


Demonstrated Inferred 


as metaP 



7,922,000 
1 ,830,000 
1 ,640,000 
2,388,000 

846,000 
14,626,000 



4,467,000 

1 ,598,000 

6,662,000 

193,000 

2,815,000 
15,735,000 



229,400 
74,600 
95,500 
50,100 

50,000 
499,600 



128,500 

58,000 

304,400 

6,900 

475,700 
973,500 



153,000 
51 ,000 
69,000 
31,000 



304,000 



'From demonstrated resources. 

2Mines in Italy and Thailand that do not produce refined antimony metal as end product. 



11 




Conodo 
Lakt Gaorgt 
Unit«(l Stat«i 
Stibnitt Hill 
Ytllow PiiM 
M«»lco 
Wodlay 
Bolivia 

Etpiritu Santo 
La Salvodoro 



T Chilcobijo 

8 Churquini 

9 Roto dt Oro 
K) Cand*loria 
// Coracoto 

Itoly 

12 Manciono 
Turk«v 

13 Turhol-Tohot 



M Tourtit 

/5 Timarhdoudin* 

South Africo 
16 Contolidottd Murchison Ltd 

Thoilond 
t7 Doi Ngown 
/* BoThonfl 
19 MmTo 



Auttrolia 
Hillgrovt 
Wild Cottl* CrMk 



LEGEND 
A Antimony d«po«it 



FIGURE 1.— Antimony mine and deposit locations. 




Demonstrated resources 



Contained antimony 



FIGURE 2.— Demonstrated antimony resources. 



112 



North America 
pet 



North America 
pet 




Inferred resources 



Contained antimony 



FIGURE 3.— Inferred antimony resources. 



BYPRODUCT ANTIMONY 

' In addition to the primary antimony resource, antimony 
is also recovered as a byproduct from the smelting and refin- 
ing of lead and silver ores. The recovery of byproduct an- 
timony in most cases is incidental to the recovery of the 
primary metals. A major domestic sovurce of byproduct an- 
timony is the Sunshine Mine. The reason Sunshine Mine 
produces antimony is that the presence of antimony is 
deleterious to silver refining. Most often antimony con- 
tained in lead ores (domestic and foreign) is not paid for by 
the smelters, because of its negative effect in processing the 
primary lead. As a result, the antimony resovu*ce base from 
this source is hard to define. 

At present, any estimate of byproduct antimony would 
be hypothetical. Some historical production data are shown 
in table 8. 

SECONDARY ANTIMONY 

Secondary antimony provides a large portion of the total 
antimony supply in most industrialized countries. In 
general, the recovery of secondary antimony is incidental 
to the recovery of the principal metal. The largest single 
source of secondary lead is antimonial lead battery scraps. 
Other sources are bearing metal, babbitt metal, and lead 
dross. Depending upon the degree of purity of the scrap 
metal, the plants either resmelt the scrap or produce a 
specification material through the addition of lead, tin, or 



antimony (6). Antimony derived from this source is normally 
consumed in secondary alloy production. 

Secondary antimony has always been an important part 
of total U.S. antimony supply. Historically, this resoiu-ce 
contributes between 30 and 60 pet of the total (6). However, 
the introduction of the lead-calcium (maintenance-free) bat- 
teries in the automotive industry will reduce the recycling 
resources. The maintenance-free batteries, aside from tak- 
ing a major portion of the battery industry, presented prob- 
lems in the collection system that would insure the com- 
plete segregation of the antimonial lead and lead-calcium 
batteries. Complete separation of these scraps is necessary, 
since mixed scrap, in certain circumstances, poses problems 
of toxicity to workers at secondary smelters. When wet, 
mixed scraps could cause the release of two highly toxic 
gases, arsine and stibine. A portion of the calcivmi content 
in mixed scrap of lead-calcium and antimonial lead oxidizes 
dvu"ing the smelting; some forms a very stable compound 
of antimony (CajSbj), making the recovery of antimony ex- 
tremely difficult. The presence of antimony in lead-calcivun 
alloys used in battery grids causes gassing, which seriously 
reduces the characteristics of maintenance-free batteries. 
These problems create difficulties for both the secondary 
smelters and the battery manufactvu-ers. Hence, it is highly 
probable that large percentages of battery scraps will not 
be recycled. Under such circumstances, the secondary 
resource is highly weakened. Production of secondary an- 
timony in the United States over the last 10-yr period is 
shown in table 9. 



13. 



Table 8.— Antimony produced as byproduct at primary lead refineries In the United States, 1975-81 

(Thousand pounds) 

Yeari 1975 1976 1977 1978 1979 1980^ 

Gross weight of ores and scrap 12,058 13,486 15,114 11,036 7,500 1,942 

Antimony content: 

Domestic ores2 536 710 1,196 1,078 416 36 

Foreign ores3 364 684 336 324 142 24 

Scrap 234 66 268 164 40 

Total 1,134 1,460 1,800 1,566 598 60 

Antimony content ... pet of gross weight 9.4 108 V^g 14^2 8^0 3.1 

M 982-84 figures have been withheld to avoid disclosing company proprietary data. 

^Includes primary residues and small quantity of antimony ore. 

^Includes foreign base bullion and small quantities of foreign antimony ores. 



1981 



7,844 



722 

370 

18 

1,110 

14.2 



Table 9.— Secondary antimony produced In the United States by l(ind of scrap and form of recovery, 1975-83 

(Thousand pounds) 



1975 



1976 



1977 



1978 



1979 



1980 



1981 



1982 



1983 



New scrap: 

Lead base 

Tin base 

Total 

Old scrap: 

Lead base 

Tin base 

Total : 

Grand total 

Form of recovery: 

In antimonial lead . 
In other lead alloys 
In tin base alloys . . 
Total 



3,810 
78 


4,232 
52 


8,074 
48 


8,064 
72 


9,426 
30 


5,358 
32 


4,206 
4 


3,322 
4 


2,892 
2 


3,888 


4,284 


8,122 


8,136 


9,456 


5,390 


4,210 


3,326 


2,894 


32,014 
26 


35,284 
30 


53,052 
28 


44,742 
34 


38,830 
24 


34,382 
14 


35,488 
14 


29,856 
10 


25,506 
8 


32,040 


35,314 


53,080 


44,776 


38,854 


34,396 


35,502 


29,866 


25,514 


35,928 


39,598 


61 ,202 


52,912 


48,310 


39,786 


39,712 


33,912 


28,408 


29,536 

6,374 

18 


32,996 

6,588 

14 


53,160 

8,026 

16 


43,240 

9,636 

36 


40,734 

7,548 

28 


33,936 

5,820 

30 


32,742 

6,952 

18 


29,206 

3,974 

12 


25,328 

3,046 

34 



35,928 



39,598 



61,202 



52,912 



48,310 



39,786 



39,712 



33,192 



28,408 



MINING AND PROCESSING TECHNOLOGY 



MINING 



Antimony deposits are small, irregular, and discon- 
tinuous ore bodies that often present problems in ore ex- 
traction. Efficient exploitation by large-scale mining opera- 
tions is limited. In some cases, mining of antimony ore is 
accomplished by unsystematic hand operations, such as in 
Thailand. Where the deposit or vein structiire warrants the 
use of large-scale mining operations, mining methods such 
as open pit, cut and fill, sublevel stoping, shrinkage, and 
open stoping are used. 

Cut and fill is primarily practiced in underground an- 
timony mines in Bolivia. Using overhand mining, the ore 
is cut in slices parallel to the level. After each cut of ore 
is mined, backfill is introduced to support the walls. 
Blasting is performed with an ammonium nitrate-fuel oil 
(ANFO) mixture with 60 pet dynamite as primer. About 1.0 
to 2.6 kg of explosives is required to fragment 1 mt ore. 

The sublevel stoping method is practiced in some an- 
timony mines that were studied. This method requires a 
minimum ore body width of 6 m in order to permit long- 
hole drilling techniques. In the Tourtit Mine, sublevels are 
driven from raises, where long-holes are ring-drilled. The 
ore is blasted with 5 pet ANFO, requiring about 0.35 kg 
of explosives to fragment 1 mt ore. 



Mining in some antimony mines is accomplished by a 
shrinkage mining method. Basically, this method is an 
overhand stoping system and is applied mostly in steeply 
dipping ore deposits. During the entire mining period, a por- 
tion of the ore is accumulated until the stope is completed. 
In a typical mining operation, as in the Timberhdoudine 
Mine (Morocco), drilling is accomplished by jacklegs with 
ANFO as the primary explosive. About 0.5 kg of explosives 
is used to fragment 1 mt ore. 

Several antimony mines use open stoping methods to 
extract ore. This mining method is commonly applied to 
stratiform deposits. CML in the Republic of South Africa 
and the Turhal Mine in Turkey utilize open stoping where 
the width of the vein is less than 3 m. Average explosive 
consumption is estimated at 0.85 kg to fragment 1 mt ore. 

Surface mining is practiced in Thailand and Italy. The 
Manciano Mine in Italy and Doi Ngoem ^ine in Thailand 
are open pit operations, where benches are maintained andj 
drilling and blasting are required to fragment the ores. Thisj 
operation requires about 0.3 kg of explosives to fragment 
1 mt ore. The other mines in Thailand extract ore by un- 1 
systematic surface mining methods. The ore is ripped by) 
bulldozers, and the exposed ores are hand picked. Oversize' 
boulders are broken by hammer and hand loaded into^ 
trucks. These operations do not maintain benches, nor do 
they use explosives to fragment the ore. 



!14 



ORE PROCESSING 

Run-of-mine ores, except direct shipping grades (5 to 
25 pet Sb), are generally upgraded to marketable products 
through crushing, grinding, and cleissifying processes. 
Beneficiation of antimony sulfide ores is normally ac- 
complished by gravity and flotation processes. Antimony 
from simple ores, those that contain only stibnite and 
siliceous materials, are easily concentrated to about 65 pet 
Sb with the use of flotation reagents such as copper sulfate 
or lead nitrate for an activator and xanthate for a collector 
(7). Beneficiation of complex antimony ores generally 
employs a flotation process along with gravity concentra- 
tion to recover the b3T)roducts. 

Oxidized antimony ores have not been successfully 
' floated. In Mexico, oxidized ores £ire normally upgraded by 
I either hand sorting or hand jigging. 

SMELTING 

Extraction of antimony from ore or concentrate is ac- 
complished by either pyrometallurgicai or electro- 
metallurgical methods. Due to the ease of volatilizing oxide 
ores as well as reducing both sulfide and oxide ores to metal, 
pyrometallurgicai extraction methods have been used more 
than electrometallurgy. Antimony metal and antimony 
trioxide can be produced in the same pyrometallvirgical 
plant by merely changing the quantities and types of flux- 
ing agents. Where oxide ores are volatilized, a special type 
of roaster is adopted in the process. The electrometallurgical 
technique is not discussed in this report since it is not used 
in general commercial application. 

Smelting antimony ores and concentrates to recover 
antimony dominates the industry owing to the relative ease 
of the extraction technique. The important characteristics 
of antimony that favor smelting include the low melting 
and boiling point of the metal, high vapor pressure, ther- 
mal dissociation, oxidation-reduction reactions, rate of 
chemical reactions, and the equilibrium established dur- 
ing the process (7). 

Antimony is smelted in blast furnaces in two distinct 
temperatvu"e reaction zones. At the initial stage of smelting, 
stibnite melts and trickles down the charges. As the molten 
sulfide reaches the temperatiu-e zone of 1,332 ° F, a portion 
of the molten sulfide is vaporized and carried upward by 
the blast. Upon reaching a temperature of 2,012° F, ther- 
mal dissociation to elemental antimony occurs. Simultane- 
ously, oxidation of the vapors to SO2 and SbaOs take place. 
Metallic antimony not vaporized or oxidized is collected 
periodically in the forehearth. Vaporized antimony passes 
through the furnace into the flue where it is cooled down. 
Upon cooling, the condensate is collected in the baghouse. 
The collection of a large volume of fumes and dusts is 
necessary to realize high recovery. The entire process 



recovers about 85 pet of the antimony content as SbjO, and 
10 pet as metallic antimony; the rest is lost in processing. 

Several variations are available in the antimony 
smelting process. One of them is the precipitation technique. 
The process takes adveintage of the greater affinity of sulfur 
for iron than for antimony. The smelting is accomplished 
by mixing fine iron scrap in the furnace charge. The iron 
reduces the stibnite to metallic antimony wth an iron sulfide 
matte. 

Products fi-om smelters are impure antimony oxides and 
metal. To attain a commercial grade, the intermediate prod- 
ucts are refined to desired products. 



REFINING 

Refining is accomplished either by a pyrometalliu-gy 
process or by electrorefining. Basically, pyrometalliu-gy 
could refine the impure metal or the antimony oxide to the 
desired final product; i.e., in times of high metal demand, 
antimony oxide is readily converted to pure metal and vice 
versa. In electrorefining, the process starts with impure 
metal and produces pure metal as the final product. 

P3Tometallurgical refining operations in most cases are 
carried on in a small reverberatory furnace. Refining begins 
with the charging and melting of impure antimony metal. 
Upon melting, a mixture of soda and coke dust is added to 
produce thick slag. In about 3 h, the slag is skimmed off. 
The impurities of iron and sulfur are then removed by add- 
ing chemical reagents such as oxysulfide of antimony and 
potash. The final slag, referred to as "star slag" and prin- 
cipally made up of antimony glass, contains 20 to 60 pet 
Sb (7). After about 15 min, the antimony metal, called 
regulus, is ladled out into molds where a starlike pattern 
is formed on the metal surface. The starred regulus usually 
is over 99.6 pet Sb (7). 

Electrolji;ie refining starts by easting the impure metal 
into anodes. Once the anodes are submerged into the 
aqueous bath, the antimony is dissolved into the solution. 
By means of electrolysis, the antimony is redeposited on 
the cathode. The impurities, generally composed of sulfur, 
iron, copper, arsenic, gold, and silver, are collected in the 
cell slimes. When present in appreciable quantities, arsenic 
and copper codeposit with antimony in the cathode. Cop- 
per is normally removed from the electrolyte by cementa- 
tion on powdered metallic antimony, but arsenic tends to 
concentrate in the electrolyte. Because distillation can only 
remove part of the arsenic from the electrolyte, antimony 
cathodes always contain a small amount of arsenic. Com- 
plete arsenic removal is possible by resmeltng the cathode 
I with an oxidizing slag composed of caustic, sodium nitrate, 
and soda ash, which removes arsenic as sodivun arsenate. 
{ The starred regulus metal produced normally is over 99.9 
,pet Sb(7). 



DEPOSIT EVALUATION PROCEDURE 



Illustrated in figure 4 is the Bureau's Minerals Avail- 
ability program (MAP) evaluation process, from deposit 
identification to the development of availability ciu^es. This 
flowsheet shows the various evaluation stages used in this 
study to assess the availability of antimony from individual 
properties. After a deposit is identified for analysis. 



engineering and economic evaluations of the property are 
performed. For nonprodueing deposits optimal mining and 
concentrating rates and other production parameters were 
chosen using current standard engineering principles. 
Startup dates for developing deposits were based on an- 
nounced company plans. For explored deposits, a near-term 



15. 



Identification 

and 

selection 

of deposits 



Tonnage 

and grade 

determination 



Engineering 
and cost 
evaluation 



^ Mineral "• 

Industries 

Location 

System 

(MILS) 

data 



MAP 

computer 

data 

base 



Taxes, 
royalties, 
cost indexes, 
prices, etc. 



Deposit 

report 

preparation 



MAP 

permanent 

deposit 

files 



Data 

selection and 

validation 



Variable and 

parameter 

adjustments 



Economic 
analysis 



Sensitivity 
analysis 



Availability 
curves 



Analytical 
reports 





Data 



Availability 
curves 



Analytical 
reports 



FIGURE 4.— Minerals availability program! deposit evaluation procedure. 



development schedule (5 to 10 yr) was chosen. Planned ex- 
pansions for operating mines were included when known. 

Information on average grades, ore tonnages, and dif- 
ferent physical characteristics affecting production was ob- 
tained from various sources, including Bureau of Mines and 
U.S. Geological Survey publications, professional journals, 
State and industry publications, company annual reports, 
lOK reports and prospectuses filed with the Securities and 
Exchange Commission, private companies, and estimates 
made by Bureau personnel. Much of the foreign data was 
collected through a Bureau contract with Brown and Root 
Development, Inc., Houston, TX. 

Selection of deposits was limited to known deposits that 
contain at least 85 pet of the demonstrated reserves and 
resources located in each country as of January 1984. 
Reserves are material that can be mined, processed, and 
marketed at a profit under prevailing economic and 
technological conditions. Resources are concentrations of 
naturally occurring solid, liquid, or gaseous materials in 
the Earth's crust in such form that economic extraction of 
a commodity is currently or potentially feasible (8). 

For the deposits analyzed, tonnage estimates were made 
at the demonstrated resoiu*ce level based on the mineral 
resource-reserve classification system developed jointly by 
the Bureau and the U.S. Greological Survey (8). The \ 
demonstrated resource category includes measured plus in- 
dicated tonnages, as shown in figure 5. Generally, reserve : 
and resource tonnages and grade calculations presented in j 
this study were computed from specific measurements, 
samples, or production data and from estimations made on 
geologic evidence. 

The objective of the study is to include mines and 
deposits that account for at least 85 pet of the antimony pro- 
duction and known resources from each significant produc- 
ing country. 



The engineering and economic analyses for each deposit 
was performed to determine the total cost necessary to pro- 
duce a specified level of output from the deposit. Total cost, 
also called commodity or incentive price, is defined as the 
average total cost of production for the deposit. In this study, 
profit computed at a 15-pct discounted-cash-flow rate of 
return (DCFROR) was included in the total cost. Total cost, 
then, is the antimony price (in constant 1984 U.S. dollars) 
at which the firm would recover its capital investment and 
make a 15-pct profit. 

Determination of the quantity of antimony that could 
be produced and the cost required to achieve this produc- 
tion was based on the following assumptions: 

1. Each operation will produce at full planned operating 
capacity throughout its life. (Capacities were based on 1984 
and/or 1984 company plans or engineering judgments.) 

2. Competition and demand conditions are such that 
each operation will be able to sell all its output at its total 
production cost. This condition implies that the level of an- 
timony demand will support the highest cost deposit, or that 
existing government subsidies will equal the difference be- 
tween the market price and the total cost for each sub- 
marginal deposit. 

3. All bjrproducts will be sold at January 1984 prices. 

4. Concentrates produced by the deposits analyzed are 
processed to refined antimony metal or refined antimony 
trioxide, the final marketable products. All antimony metal 
is sold f.o.b. plant. 

Time lags involved in filing environmental impact 
statements and receiving necessary pemiits, financing, etc., 
were not included in the analysis. Existing laws and regula- 
tions, environmental, political, legal, or other constraints 
may limit production from some of the deposits included I 
in this study. 



16 



Cumulative 
production 


IDENTIFIED RESOURCES 


UNDISCOVERED RESOURCES 


Demonstrated 


Inferred 


Probability range 


Measured Indicated 


Hypothetical i Speculative 




ECONOMIC 


Reserve 


Inferred 

reserve 

base 


1 
+ 

1 


MARGINALLY 
ECONOMIC 


base 


SUB- 
ECONOMIC 




1 





Other 
occurrences 



Includes nonconventional and low-grade materials 



FIGURE 5.— Mineral resource classification categories. 



The byproduct prices (gold, $370.89/tr oz) used in this 
study were based on January 1984 information. Because 
the study was conducted using constant January 1984 
dollars, no escalation of either costs or prices was included. 

For each operation included in an economic evaluation, 
capital expenditures were calculated for exploration, ac- 
quisition, development, mine plant and mine equipment, 
'and constructing and equipping the mill. The capital ex- 
penditvires for the different mining and processing facilities 
include the costs of mobile and stationary equipment, con- 
struction, engineering, infrastructure, and working capital. 
Infrastructure is a broad category that includes costs for 
access and haulage facilities, ports, water facilities, power 
supply, and personnel accommodations. Working capital is 
a revolving cash fund required for operating expenses such 
as labor, supplies, insurance, and taxes. All costs were in 
'U.S. dollar terms. 

The initial capital costs for producing or past produc- 
ing mines have been depreciated according to the actual 
investment year, and the undepreciated portion was treated 
as a capital investment in 1984, the year of costs for this 
evaluation. Reinvestments will vary according to capacity, 
production life, and age of the facilities. Where appropriate, 
costs have been updated to January 1984 U.S. dollars ac- 
cording to local currency factors and individual coimtry in- 
flation indexes, weighted proportionately by the impact of 
labor, energy, and capital in the antimony industry on a 
countrywide basis. 

The total operating cost of a mining project is a com- 
bination of direct and indirect costs. Direct operating costs 
include operating and maintenance labor and supplies, 
supervision, pajrroU overhead, insurance, local taxation, and 
utilities. The indirect operating costs include technical and 
clerical labor, administrative costs, maintenance of 
facilities, and research. 



When available, actual company cost data were used. 
If these data were not available, the required capital and 
operating costs were estimated by standardized costing 
techniques. In some cases, costs were estimated from the 
Bureau's cost estimating system (CES) (9). This system is 
designed to prepare a prefeasibility type estimate for capital 
and operating costs based on an average cost derived from 
U.S. and Canadian mining operations. Index value for each 
cost component allows the system to update cost for time, 
geographic locations, labor rates, and specific mining and 
milling conditions. Correct use of CES usually generate 
costs within ±25 pet of the actual cost. 

After production parameters and costs for the develop- 
ment of antimony deposits were established, the supply 
analysis model (SAM) (10) was used to perform various 
economic evaluations pertaining to the potential availabil- 
ity of antimony. The SAM system is a comprehensive 
economic evaluation simulator that is used to determine 
the constant-dollar long-run price at which the primary com- 
modity must be sold to recover all costs of production, in- 
cluding a prespecified DCFROR on investment, less all 
b5T)roduct revenues. The DCFROR is the ROR that makes 
the present worth of cash flows from an investment equal 
to the present worth of all after-tax investment ill). The 
rate of 15 pet was considered the minimum return on in- 
vestment sufficient to attract new capital to the industry. 
Some government-owned operations utilize criteria other 
than economics to justify continued operation. However, for 
comparison purposes, each deposit was analyzed at 15-pct 
DCFROR. 

The SAM contains a separate tax records file for each 
State and country that includes all the relevant tax 
parameters under which a mining firm would operate. 
These tax parameters are applied to each mineral deposit 
under evaluation with the implicit assumption that each 



.17, 



deposit represents a separate corporate entity. In reality, 
properties belonging to the same corporation would have 
certain tax advantages not assvimed for this evaluation. 
Other costs in the analysis include standard deductibles 
such as depreciation, depletion, deferred expenses, invest- 



ment tax credits, and tax loss canyforwards. The SAM also 
contains a separate file of economic indexes to allow for up- 
dating all cost estimates for producing and nonproducing 
operations. 



CAPITAL AND OPERATING COSTS 



Capital costs for 21 properties, 12 producers, and 9 non- 
producers and past producers were evaluated. Since all pro- 
ducing mines have been in production for a nimaber of years, 
almost all investments have already been depreciated. Any 
current and future investments incurred by these operations 
are limited to eqviipment replacement cost or cost of expan- 
sion if any. Capital investments to reopen the nonproduc- 
ing mines (p£ist producers) are limited to rehabilitation costs 
and therefore do not refiect the same costs encountered in 
developing virgin deposits. As a result, capital cost data are 
not presented in this report. 

The average total operating costs calculated for each of 
the deposits analyzed included mining, milling, transpor- 
tation, taxes, smelting and refining, and bjT)roduct credit; 
these costs are presented in table 10. Mine and mill 
operating costs include all costs for labor, energy, supplies, 
and indirect costs of administration, maintenance, 
overhead, and insurance. The "other costs" category in- 
cludes recovery of capital and a 15-pct DCFROR on invested 
capital. Operating costs often vary greatly, depending on 
such factors as size of operation, mining method, deposit , 
location, stripping ratio, depth of ore body, grade of ore, proc- 
essing losses, energy and labor costs, and applicable tax 
structure. The costs presented in this section are based on 
mining and milling the ore over the life of the operation. 

As shown in table 10, the mine operating costs vary fi"om 
$11.18/mt to $42.67/mt ore. The difference in cost is mainly 
because of the mining method used in the operations. The 
mines in Asia and Australia use expensive underground 



timbered open stoping or cut-and-fill methods, whereas 
Latin American mines utilize open cut, open stope, and stan- 
dard cut and fill. In addition, labor costs in Latin America 
are much lower than those in Afi:dca and Australia. 

In milling operations, Asia-Australia also shows the 
highest production costs, mainly because of the added cost 
incmred in the recovery of gold as a b5T)roduct. Gold values, 
however, Eu-e credited to the value of recovered antimony 
metal. Such values are, however, not offsetting, suggesting 
that it may not be economical to recover gold. Latin America 
shows the lowest milling cost, chiefly due to low labor costs. 
In addition, one mine produces a direct shipping ore, thus 
incurring no milling cost. 

When production cost is converted to dollars per pound 
of antimony recovered, the United States and Canada have 
the highest production costs. The high costs are mainly 
because of expensive labor costs, high taxation, and process- 
ing of low-grade ore. Latin America, due to its low labor 
cost and high-grade ores, shows the lowest production costs 
for both mine and mill operations. 

Costs for African mines reflect their expensive smelter 
and refining costs. Most African ores are smelted and re- 
fined in European countries where labor and energy costs 
are high. On the other hand, most of the ores in Latin 
America are smelted and refined in domestic plants. 

When bjT)roduct credits are removed from the total 
operating costs, the Asia- Australia mines become the most 
expensive operations, chiefly because of their expensive 
mining methods. 



Table 10.— Estimated weighted-average operating and total production costs 



North America 



Latin America 



Asia and 
Australia 



Africa 



Others' 



Number of mines 

Total recoverable ore mt . 

Weighted-average grade pet Sb. 

Total recoverable Sb mt. 

Production costs, $/mt ore: 

Mine operation 

Mill operation 

Operating costs, $/lb Sb in concentrate: 

Mine operation 

Mill operation 

Smelter and refining 

Transportation 

Tax 

Subtotal 

Byproduct credit 

Net cost 

Other costs* 

Total (15-pct DCFROR) 

Total (0-pct DCFROR) 

NAp Not applicable. 

'Mines that produce products other than antimony metal. 

^Includes a 15-pct DCFROR and capital recovery. 



2,490,000 

1.72 

31,189 



$11.18 
$11.69 



$.95 



8 

1,675,000 

5.14 

69,033 



$13.72 
$6.40 



$.48 



1,924,000 

3.70 

50,980 



$42.67 
$15.24 



$1.29 



7,091 ,000 

2.75 

152,648 



$28.04 
$10.28 



$1.06 



849,000 
5.84 
NAp 



$12.32 
$9.05 



$0.40 


$0.15 


$0.73 


$0.59 


NAp 


.42 


.07 


.26 


.21 


NAp 


.17 


.11 


.23 


.28 


NAp 


.11 


.05 


.06 


.19 


NAp 


.26 


.09 


.06 


.09 


NAp 


1.36 


.47 


1.34 


'1.36 


NAp 


(.37) 


(NA) 


(.13) 


(.20) 


NAp 


.99 


.47 


1.21 


1.16 


NAp 


.51 


.11 


.20 


.04 


NAp 


1.50 


.58 


1.41 


1.20 


NAp 



NAp 



lis: 



When other costs such as a 15-pct DCFROR and capital 
recovery are added to the net cost, the United States and 
Canada have the highest production costs. The U.S. and 
Canadian operations have much higher capital recovery 
costs than the Latin American operations. In contrast to 
U.S.-Canadian operations, most Latin American mines have 
been in operation for quite a long time; therefore, most of 
their capital investments have been fully depreciated. 

Transportation cost reflects the total costs of transport- 
'ing the mill concentrate to the smelter. These costs may 
include one or a combination of trucking, railroad transpor- 
tation, ocean freight, insvirance, and handling costs. As 
shown in table 10, operations in Africa reflect the highest 



transportation cost, because of the added costs of land £md 
oceem transportation to European smelters, including ad- 
ditional handling and insiu'ance costs, for many African con- 
centrates. Latin America shows the least expensive 
transportation costs, because large amounts of the concen- 
trates are smelted within relatively short trucking-railroad 
transportation distances. 

Production costs at 0-pct DCFROR reflect what opera- 
tions could produce at the breakeven level and cover all pro- 
duction costs after applying bjrproduct credit. Hence, 0-pct 
DCFROR as shown in the table should not be interpreted 
as the cash cost equivalent used in the industry. 



ANTIMONY AVAILABILITY 



After cost and resource data were determined for each 
selected property, total and annued antimony availability 
curves were constructed. A total resource availability curve 
is an aggregate of the total production potential at a 
stipulated cost that covers full production costs. Individual 
annual avEiilability curves for (producing and nonproduc- 
ing) mines were constructed to determine the cost-tonnage 
relationship of the resources on an annual basis. The curves 
reflect the antimony capacity of the properties that were 
studied. For nonproducing properties that were temporarily 
closed, the time lags required to reactivate the mines 
depended upon the rehabilitation work needed to bring the 
property back into production. Of the 21 properties 
evaluated and costed for this study, three properties from 
Thailand and one from Italy have been excluded from 
availability curves. Besides the limited recoverable an- 
timony resources from these properties, the final end prod- 
uct, a crude metal, has a very limited application and is 
used within the country. 



TOTAL AVAILABILITY 

At the demonstrated resource level, potential re- 
coverable antimony from market economy countries was 
estimated at 304,000 mt Sb from 17 properties (figure 6 and 
table 11). Mines in Africa and Latin America account for 
50 and 23 pet, respectively, of the total recoverable an- 
timony (table 11). Producing mines account for nearly 75 
pet of this total. In 1984, when antimony metal was selling 
at an average price of $1.68/lb, approximately 293,700 mt 
Sb could be produced from MEC's at a 15-pct DCFROR. 
However, at this price, no U.S. deposit can produce and earn 
a 15-pct DCFROR. 

This economic analysis is limited to resources on a 
demonstrated level. Although an additional estimated ton- 
nage of 973,500 mt of contained antimony could be available 
from the inferred resource at some of the deposits, no 
economic evaluation was performed of this resource. 



ANNUAL AVAILABILITY 

Table 12 shows the potential annual production capacity 
from the 17 properties analyzed. Production capacity rep- 
resents the average annual production in metric tons of an- 
timony metal over the life of the property. Assiiming all 
the properties are in operation, the average annual produc- 
tion from these properties is estimated at 29,200 mt/yr Sb. 



Potential annual antimony production from producing 
mines at various total production cost ranges, including a 
15-pct DCFROR, is shown in figure 7. The production levels 
shown represent the annual antimony output potential at 
full capacity for the selected total production cost range. 
For example, in 1984 the capacity potential at a total cost 
of production of $1.65 or below was estimated at 19,700 mt 
Sb. The initial rise of the curves in 1985 is due to expan- 




TOTAL RECOVERMLE ANTIMONY, 10* Mt 

FIGURE 6.— Total recoverable demonstrated antimony 
resources from producing and nonproducing properties. 



Table 1 1 .—Primary antimony potentially available from mines 

and deposits at selected cost ranges, including a 15-pct 

DCFROR 

(Metric tons) 



Antimony price, 
$/lb 


North 
America 


Latin 
America 


Asia and 
Australia 


Africa 


Total 


Under $0.55 . . . . 
$0.56 to $1.15 .. 
$1.16 to $2.00 .. 
$2.01 to $3.00 . . 




. 20,500 

500 

. 10,300 


9,300 

59,800 







11,700 
39,300 






9,700 

142,900 




9,300 

101,700 

182,700 

10,300 


Total 


. 31,300 


69,100 


51,000 


152,600 


304,000 



Table 12.— Primary annual production capacity for primary 
antimony at a 15-pct DCFROR 

(Metric tons) 



Antimony price, 
$/lb 


North 
America 


Utin 
America 


Asia and 
Australia 


Africa 


Total 


Under $0.55 .... 
$0.56 to $1.15 .. 
$1.16 to $2.00 .. 
$2.01 to $3.00 . . 




. 2,300 

200 

900 


2,800 

6,500 







2,900 
1,400 






1,000 

11,200 




2,800 

12,700 

12,800 

900 


Total 


. 3,400 


9,300 


4,300 


12,200 


29,200 



19. 



Zif I 



20-/ 



t 



T 



T 



T" 



I I I 

Antimony pricMort in JanMvy IM4 
dellart ptr pound 

INFeimEO RC SOUHCES 

ThCM fttOllfCM Qi9 titt MrtVMMn ffO 

thMf propcrtiM; ^Mntityondcott 



/ \0-»I.M 



i 



.0-1 1.00 




.ST 



FIGURE 7.— Potential annual availability from producing 
properties at a 15-pct DCFROR. 

sion of capacity at one mine. The subsequent declines in 
the curves mark the depletion of the demonstrated resources 
from four mines. At this time, it is expected that the in- 
ferred resources will be upgraded to the demonstrated level, 
probably at a price much higher than the prices prevailing 
in January 1984. This is because most of the inferred 
resources have lower grades and are at greater depth fac- 
tors that would increase production costs. Figure 7 shows 
the probable availability of antimony from inferred 
resource. If the price were to increase, incentives to search 
for and explore new deposits would take effect. 

Annual availability curves for nonproducing mines were 
based on the assiunption that rehabilitation work would 
begin in year N, because startup dates were not known. (See 
figure 8.) These curves indicate that lead time would be re- 
quired before any production could occvir. The nonproduc- 
ing properties could contribute 9,500 mt Sb annually at a 
total production cost ranging from $0.56 to $3/lb (table 13). 
The demonstrated resources from these nonproducing mines 
and the number of productive years are small, luiless the 
inferred resources are geologically and economically 
reevaluated and upgraded to the demonstrated level. 

The producing mines have a total capacity of 19,700 
mt/yr Sb. The total production costs for operating mines 
rsmge from $0.55/lb to $2/lb, with an average cost estimated 
at $0.97/lb Sb. Assimiing a production cost of $0.55/lb Sb, , 
2,800 mt/5rr Sb would be available from two producing mines 
in Latin America. At production costs up to $1.15/lb Sb, ad- 
ditional capacity of 5,300 mt/yr Sb would be available from ; 



_ iNFcmco ttcsouRcca 
Tti wo i«M My«ttit ««wn«ion tiom t ftoii 
pfOpsrtMti Quontityondcoit unMrtoin 




N'f* 
YEAR 



N't- 10 



N-fe 



FIGURE 8.— Potential annual availability from nonproducing 
properties at a 15-pct DCFROR. 

four producing mines, three in Latin America and one in 
Africa. At production costs up to $2/lb Sb, the three pro- 
ducing properties (CML, Hillgrove, and Turhal-Tokat) 
would contribute additional capacity of 11,600 mt/jrr Sb. 
Assmning (demonstrated level) the total mine capacity 
of 29,200 mt/5T Sb from producers and nonproducers is con- 
sumed each year, the potential recoverable antimony from 
MEC's would be depleted in 11 yr. The available resource 
at a price of $1.15/lb Sb would be depleted in 4 yr. Consider- 
ing domestic resoiurces, at a mining capacity of 1,100 mt/jrr 
Sb, the total potential recoverable resources would last for 
10 yr. However, if production capacity has to increase to 
fill the domestic requirement, the same recoverable resource 
would be depleted in less than a year. This mine life, 
however, can be offset if the inferred resovirces are geolog- 
ically and economically reevaluated and found to be feasi- 
ble for mining. Another possibility is to discover new 
deposits. 

Table 13.— Distribution of potential annual capacity from pro- 
ducers and nonproducers at a 15-pct DCFROR 



Antimony price, 
$/lb 


North 
America 


Latin 
America 


Asia and 
Australia 


Africa 


Total 


PRODUCERS 


Under $0.55 .... 
$0.56 to $1.15 .. 
$1.16 to $2.00 .. 
$2.01 to $3.00 . . 
Total .... 









2,800 

4,300 





7,100 





1,400 


1,400 




1,000 

10,200 



11,200 


2,600 
5,300 

11,600 


19,700 


NONPRODUCERS 


Under $0.55 .... 
$0.56 to $1.15 .. 
$1.16 to $2.00 .. 
$2.01 to $3.00 . . 
Total .... 




. 2,300 

200 

900 

. 3,400 




2,200 





2,200 




2,900 





2,900 





1,000 


1,000 




7,400 

1,200 

900 

9,500 



34Sv« 44 



.20 



CONCLUSIONS 



The United States, with two nonproducing primary an- 
timony properties as of 1984, has 10,700 mt of recoverable 
antimony or about 3.5 pet of the total recoverable resources 
contained in the properties evaluated in MEC's. Production 
capacity from these two domestic properties is estimated 
at 1,100 mt/yr Sb or 3.7 pet of total MEC annual capacity. 
This domestic production capacity represents 9.9 pet of the 
total domestic industrial requirements of 11,081 mt/jn- Sb, 
averaged over a 10-yr period. However, antimony prices well 
above those prevailing in January 1984 would be required 
in order for these deposits to be economically available. 

At a total production cost of $1.15/lb, 111,000 mt Sb 
could be profitably recovered from MEC's primary mines. 
At the prevailing January 1984 price of $1.68/lb, nine prop- 
erties (all producing mines at the time of study) could pro- 
duce profitably. At this price, no domestic property could 
recover antimony economically. If the price were to increase 
to $2/lb, an estimated additional 182,700 mt Sb would be 
available from producing and nonproducing mines. One 
domestic property would be able to operate profitably. The 
remaining resource of 10,300 mt Sb would be available at 
a total production cost between $2/lb and $3/lb. 



The United States, with its high degree of industrial 
activity, normally imports and consumes 30 to 50 pet of the 
total annual mine production from the MEC's. With such 
a small percentage of the MEC's resources located in the 
United States, the United States will probably continue to 
rely on foreign antimony to satisfy domestic industrial re- 
quirements. The most probable sources of U.S. antimony 
supply £ire Mexico, Bolivia, the Republic of South Africa, 
and China. 

Even though bjT)roduct and secondary antimony sup- 
ply a major part of the antimony production, these sources 
were not analyzed because there is no definable resource 
base as previously explained. The three properties in 
Thailand that were not included in the availability curves 
were projected to produce only crude antimony metal (72 
pet Sb), which is used in Thailand. One property in Italy 
producing impure antimony sis a fill-in for a battery recycl- 
ing plant is also not included in the availability curves. 

To gain a better imderstanding of the total availability, 
byproduct and secondary antimony must be studied and 
analyzed. 



REFERENCES 



1. Roskill Information Services Ltd. The Economics of An- 
timony. 5th ed., 1983, 140 pp. 

2. Industrial Minerals (London). Antimony— Price Recovery as 
Production Falls. No. 198, Mar. 1984, pp. 37-51. 

3. Plvmkert, P. A. Antimony. Ch. in Mineral Facts and Prob- 
lems, 1985 Edition. BuMines B 675, 1985, pp. 33-42. 

4. Miller, M. H. Antimony. Ch. in United States Mineral 
Resources. U.S. Geol. Surv. Prof. Paper 820, 1973, pp. 45-49. 

5. Dana, E. S. and W. E. Ford. A Textbook of Mineralogy. 
Wiley, 4th ed., Mar. 1932, pp. 442-443, 445, 448, 453, 477. 

6. National Materials Advisory Board. Trends and Usage of 
Antimony. Natl. Acad. Sci., Washington, DC, NMAB-274, Dec. 
1970, 113 pp. 

7. U.S. Bureau of Mines. Materials Survey— Antimony. MS-1, 
Mar. 1951, pp. 1-9 and IV-29. 

8. U.S. Bureau ofMines and U.S. Geological Svu-vey. Principles 



of a Resoiu-ce/Reserve Classification for Minerals. U.S. Geol. Surv. 
Circ. 831, 1980, 5 pp. 

9. Clement, G. K., Jr., R. L. Miller, P. A. Seibert, L. Avery, 
and H. Bennett. Capital and Operating Cost Estimating System 
Manual for Mining and Beneficiation of Metallic and Nonmetallic 
Minerals Except Fossil Fuels in the United States and Canada. 
BuMines Special Publ., 1980, 149 pp. Also available as— STRAAM 
Engineers, Inc. Capital and Operating Cost Estimating System 
Handbook— Mining and Beneficiation of Metallic and Nonmetallic 
Minerals Except Fossil Fuels in the United States and Canada (con- 
tract JO255026). BuMines OFR 10-78, 1977, 382 pp. 

10. DavidofF, R. L. Supply Analysis Model (SAM): A Minerals 
Availability System Methodology. BuMines IC 8820, 1980, 45 pp. 

11. Stermole, F. J. Economic Evaluation and Investment Deci- 
sion Methods. Investment Evaluation Corp., Golden, CO, 2d ed., 
1974, 443 pp. 



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